Front end loader with variable actuating arm



Dec. 6, 1955 E. F. slLBAuGH FRONT END LOADER WITH VARIABLE ACTUATING ARM2 Sheets-Sheet l Filed Jan. 2, 1955 Dec. 6, 1955 E. F. sxLBAUGH2,725,995

FRONT END LOADER WITH VARIABLE ACTUATING ARM Filed Jan. 2, 1953 2Sheets-Sheet 2 United States Patent Office FRONT END LOADER WITHVARIABLE ACTUATING ARM Elmer F. silbaugh, Humboldt, Iowa ApplicationJanuary 2, 1953, Serial No. 329,225

' s claims. (ci. 214-131) This invention relates generally to front endloaders and particularly to a front end loader with an automaticallyvariable actuating lever arm.

In the design of front end loaders and the like it has been well knownin the field that materially greater lifting force is required at thelower load elevations than at the upper. This is due to the longerhorizontal load lever arm during the lower portion of the stroke as wellas to the vexcessive force required to break the load loose at thebottom of the lifting stroke. It is also important that as much speed isproduced in the lifting stroke as possible and particularly during theupper portion thereof where the lifting force required can be materiallyreduced. The uid capacity of hydraulic systems is also a criticalconsideration in the design of the hoisting mechanism for the front endloaders and, of course, the smaller the actuating rams, the smaller thereserve of fluid supply required and also the faster the possibleelevating speed of the boom.

It is therefore an object of my present invention to provide a front endloader for farm tractors and the like which varies the applied liftingforce with the requirements produced by the varying resisting forceproduced by` the load during the various portions of the lifting stroke.

It isafurther object to provide a front end loader having a liftingmechanism constructed to exert its maximumlifting force until the fullboom extension position is obtained andy to progressively reduce thelifting force exerted on the boom as 'the same is elevated above itsfully extended position.

It is another object to provide a front end loader having a liftingmechanism adapted to exert its lifting force on an actuating lever armof maximum length during the lower portion of the lifting stroke andprogressively shortening said actuating arm during the upper portion ofsaid lifting stroke, permitting the maximum lifting force to be exertedduring the lower portion of said stroke where it is required andincreasing the elevating speed during the upper portion of the liftingstroke.

More specifically, it is an object to provide a front end loader havinga pair of swingably mounted booms, each having a slideable connectionintermediately mounted thereon for attachment of a hydraulicallyactuated lifting mechanism with link means attached to said slidingconnections for shifting the same toward the respective pivot points ofthe booms to shorten the actuating lever arms of said booms as the sameare raised above horizontal position, but constructed to maintain themaximum actuating arm during elevation to horizontal fully extendedposition.

These and other objects and advantages of my invention will more fullyappear from the following description made in connection with theaccompanying drawings wherein like reference characters refer to thesame or similar parts throughout the several views and in which:

Fig. lis a side elevational view showing my new loader attachment withthe scoop in lowered position by full lines and in progressively raisedpositions by dotted lines; Fig. 2 is a top plan view thereof; Fig. 3 isa fragmentary sectional view taken ksubstantially along the line 3 3 ofFig. 1; and

Fig. 4 is a fragmentary sectional view taken substantally along the line4 4 of Fig. 1 and showing the attachment of the arm shortening link withthe boom mounting member. l

As illustrated in the accompanying drawings, I provide a conventionalfarm tractor designated as an entirety by theV numeral 7 and having apair of longitudinal frame members 8 disposed along the sides thereof inthe usual manner. The tractor 7 isrprovided with a rear axle 9 on whichrear wheels 10 are mounted. The front wheels 11, of course, steer thetractor and are mounted in a conventional manner.

The ease with which my loader can be mounted on the tractor is animportant feature thereof. The pair of longitudinally disposed rigidmounting members 12 are adapted to be very easily attached to thetractor as best shown in Figs. l and 2. A forward mounting bracket 13 isrigidly fixed to the forward portion ofv each tractor frame member 8 asby the plurality of attachment bolts l 14 and each bracket 13 has alaterally outstanding attachment member 13a as best shown in Fig. 2. Theforward end of each longitudinal mounting member 12 is securely anchoredto outer portion of the respective laterally outstanding attachmentmembers 13a as by a pair of U bolts 15 embracing the forward portions ofeach of'the mounting members 12. The rear ends of the two longitudinalmounting members 12 are securely anchored to the respective sides of therear axle 9 as by the U bolts 16.

An upstanding boom supporting structure 17 is mounted in fixed relationon an intermediate portion of each of the mounting members 12 and thetwo upstanding mounting structures 17 as by the pivot pins 20. Theforward end portions of the two boom members 19 are rigidlyinterconnected by the bracing structure 21 as shown in Fig. Zand a scoopmember 22 is pivotally mounted on said forward boom portions in aconventional manner. In the form shown, the booms 19 are suitablyreinforced by the overlying tie rods 19a asbest shown in Fig. 1. Y

The boom elevating mechanism consists in a pair of inclined hydraulicrams 23 having theirlowerrear end portions respectively pivoted to thelower portions of the upstanding structures 17 as best shown in Fig. l.A slidable sleeve 24 is shiftably mounted for longitudinal,` movementalong intermediate portions of each of the, booms 19 as best shown inFigs. 1 and 2. A depending attachment web 24a is securely fixed to thelower portion of each of the sleeves 24. The upper forward ends oftherams 23 are respectively pivoted to intermediate portions of saidattachment webs 24a asbest shown in Fig. 1. ment of the sleeves 24 alongthe booms 19 are provided such as the stop collars 25 which arerespectively fixed to the booms 19 as by being welded thereto.

In order to provide the desired shifting movement ofA the sleeves 24when the booms are swung upwardly beyond their horizontal fullyextending position, an arm shortening link 26 is pivotally attached atits forward end to each of the webs 24a and the rear ends of saidlinkslv 26 arevrespectively pivotally connected to intermediate portionsof the upstanding supporting structures 17 as by pivot pins 17a.spective supporting structure 17 and the rear end of the respective link26 attached thereto, is made in the ,formr shown, by a clevis 27 havinga guiding sleeve 27a rigidly attached thereto. It is'necessary that alimited amount of free extensibility of links 26 be provided Vbefore thesame.

begin to pull downwardly and rearwardly on the sleeves Patented Dec. s,1955` Suitable means for limiting the forward move-- This pivotalconnection between ythe re- 3 24 to which.Y thesameare. connected sincethe actuating arms should not be shortened until after the booms 19 havebeen raised above horizontal position where, of course, the load isapplied to the maximum horizontal lever. arm; In` the: formtshown',this'extensibilityl isfprovided by a lost motion connectiolrbetweenitheclevis- Z7 and= a: rod 26afslidably received throughthe guiding sleeve27a and forming the rear 'endportionof link 2'6. Suitable stop meansare; provided:` at; the rear endlof: each rodf 265.'

such as the: adjustable. nut 261i which' engages-the. outenV end:portion of. clevis 25T after.' the` rodv portion' 26a has moved apredetermined distance outwardly through the clevis. 2.7 andguidingsleevef27a. Until-.the stop` nut 25h actually-` movesL intorengagement with the endof the clevis:

27,` the` actuating armxof eachoftlie'hooms 19 will remain atA amaximumlength andno' shorteningzthereofi will' take' place.' However, uponlengagement ofthe stop nuts` Zeb' the` arm: shortening links- 25 actuallybegintheir armv shortening: function, I have provided a verticaladjustment oftheclevis mounting pin 17'aat the rear of each of thelinks'26. This verticaladjustment is permitted by selectivelyinsertingthe pivot pin 17a in oneA ofv a plurality of holes 1-lb formed througheach upstanding supporting structure 17l As bestr shown in Figs. 3and 4,each of` these upstanding structures 17v is constructed of a pair ofspaced opstanding plates 17t` interconnected at their rear: edgesby aweb plate 17d and the clevis 27f is interposed between saidtwo-plateswith'the pin 17a extending through both plates and through the rearportion of the clevis asbest shown in Fig. 4. The adjustment of theelevation of pinsv 17a, ofcourse, varies the rate-at which the actuatingarms of? the booms 19 are shortened by varying the relative pivot pointsof' the booms 19 and thelinks 26.

The following is a description of the` assembly and operation of myimproved front and loader mechanism; The longitudinal mounting members12l are securelyanchored to the tractor, as hasbeen-previously'described;

bythe use of the U bolts 15,' which permit'the'space be- 1 tween therear axl'e 9 of the tractor and the forward* attachment mountingbrackets 13"to beeasily varied which', of course, greatly simplifies theattachment` of said lon'- gitudinal members 12. After said'members12have been secured to the tractor, the booms` 19 are respectivelymounted on-theupper portions of theupstanding support;- ing structures1-7 and the ramsV 23` and links 26 respec= tively connected to thedepending'websA 24U. 'Ihe rams 23 are connectedin the usuallmanner toa`conventional hydraulicspump (not shown) which may be a part'ofthetractor equipment. by driving a tractor into thepile of material to bevelevated, and a large breaking'f'orce is applied to initially elevatethe loaded scoop` from thev ground. The scoopV isthenelevatedlprogressively as shownby the'do'tted line.

positions of Fig; 1'. Thelostl motion connections respectively providedbetween the links 26 and the respective clevises 27 permits the sleeves24 to remainV in forwardly projectedr position againstV the respective`stop' collars 25' until the boom has been elevated at leastinto'horizontalj Above this limit; tlierstopl nutsl fully extendedposition. 26b will engage the ends of clevises 27 andcause therespectivesleeves 24 tobeshifted rearwardlyas'shown by the upper dotted positionsof Fig; ltwherein. the sleevesY are spaced rearwardly from`thecoll'rs25. This shorten- The scoop 22" is,` of course, filled'.

ing is, ofcourse, due to the spaced relation between the pivot points ofthe booms 19 andthe links 26 21nd,. as.

has been pointed out, this spaced relationship can be adjusted byvarying the positions of the link pivot pins 17a.

It will be seen that I have provided a relatively simple yet highlyeflicient front end loader with a controllably variable actuating leverarm which is progressively shortened after the load has beenv elevatedabove a predeterminedlimit to'permit not only faster elevation` ofi theload at the higher elevations thereof, but also to permit materiallyless fiuid to be required than is normally the case where the actuatinglever arm remains constant throughout the entire elevating structuren onthe boom.

It will, of course, be understood that various changes may be made intheform, details: arrangement and proportions of the parts withoutdeparting from the scope of my invention, which generally stated,consists of the matter shown and described herein and set forth in theappended claims.

What-l claim is:

l. A hoisting mechanism comprising a supporting structure adapted to bemounted on awheeled'vehicle, a

forwardly extending boom pivotally mounted' at its rear` end on saidsupporting structure for swinging` movement onv a horizontal'transversely disposed axis, a ram'mountl ing member'slidably mounted onan intermediate portiony of said boom in forwardly spaced relation. tothe pivotal axis of the boom, a hydraulic ram connected at its rear endto said supporting structure and extending generally forwardly therefromand pivotally connected at its-forward end to said slidable mountingmember, positive. stop` means connected to said boom and constructed toposi` tively limit the forward sliding movement ofthe mounting member, ashortening link connected at its forward end to said mounting member andits rear end to said. supporting structure in spaced relation below thepivotal. axis ofthe boom whereby the tensile force exerted by said linkbetween said mounting and said. supporting stnucture when said boom iselevated by saidlramyvill. pull said slidable mountingmember rearwardlyon said. boomto shorten the actuating lever armof the ram on the boom.

2. The structure set forth inV claim l and the rean end ofsaid ram beingmounted a substantial distancebelow the pivotal axis of said boom, sothat forcible extension of said ram willproduce elevationof said boom.

3. A hoisting mechanism comprisingl asupporting` structure, a boompivotally mounted at its rear endfon` said` supporting structurefor.swinging movement on a horizontal axis disposed transversely of saidvboom, amounting member shiftably mounted on saidhoorn` in' forwardlyspaced relation to the transverseA pivotal axisthereoffor back and forthmovement longitudinally'of the boom, positive stop means xedto said4boom stru tureand positivelyV limiting the forward shifting move ment ofthe-mounting member, lifting mechanism opera'- tively associated withsaid mounting member fox'. exerting."

liftingV force on` said boom, and a shortening linkl interconnecting`said mountingmember and. said supponlngj structure in4 a manner. toshift. said mounting memberl rearwardly on said; boomitoward thepivotall axis1thereofto'shorten the actuatingarm;thereof as the boom' isele; vated` by said lifting` mechanism, said shortening link` havingprovision for limited initial extension to'permit` saidboom to beelevated. a predetermined distance before the actuatingarmA thereof isshortened by said link.

4. A front end loader for farmtractors and the like comprising a boomsupporting structure adapted-tube mounted. in fixed relation on a farmtractor, a pair of transverselyspaced generally forwardlyextendingsubstantially parallel booms pivotally mounted on.said supportingstructure for swiging movement on a horizontal axisdisposedtransverselyv of said booms, a-pair ofgenerally. forwardlyextending. hydraulically. actuatedV boom.

lifting rams respectively connected at their rear ends to said boommounting structures in spaced relation below the pivotal mountings ofthe two booms, a mounting slide mounted on each of said booms at apointdisposed in forwardly spaced relation to the pivotal mountings thereofand said mounting slides being respectively connected to the forwardends of said rams, a pair of generally forwardly extending shorteninglinks respectively connecting said slides with portions of said boommounting structure disposed in spaced relation below the pivotalmountings of the booms thereon whereby said mounting slides arerespectively shifted toward the pivotal mountings of said booms as thesame are elevated, and means rigidly interconnecting the forwardportions of said booms to form a single hydraulically actuated boomstructure.

5. A hoisting mechanism comprising a lsupporting structure adapted to bemounted on a wheeled vehicle, a boom pivotally mounted at its rear endon said sup- .porting structure for swinging movement on a horizontaltransversely disposed axis, a mounting member' shiftably mounted on saidboom in forwardly spaced relation to the pivotal mounting thereof forback and forth longitudinal shifting movement on said boom, meansengaging said mounting member and positively the forward shiftingmovement thereof to provide a maximum actuating lever arm for theinitial lifting movement of the boom, lifting mechanism operativelyassociated with said mounting member for exerting lifting force on saidboom, a shortening link connected at its forward end to said mountingmember and at its rear end to said supporting structure in downwardlyspaced relation below the pivotal boom mounting, the rear connection ofthe shortening link with the supporting structure permitting limitedfree extensibility of said link during the initial lifting movement ofsaid boom but shifting said mounting member toward said boom pivot whenthis limited initial shifting movement has been reached, and

lmeans permitting the adjustment of said free extensibility to vary theinitial operating point of said shortening link.

References Cited in the tile of this patent UNITED STATES PATENTS2,465,476 Pokorny et al Mar. 29, 1949 2,468,602 Lord Apr. 26, 19492,501,797 Ulrich Mar. 28, 1950 2,524,203 Mott Oct. 3, 1950

